Start by clicking the Last Import item in the Library area. This is the fastest way to access the most recent set of shots.
Selective viewing. Adjust the size of the photo thumbnails to your liking: jump down to the lower-left corner and use the Zoom slider.
To magnify a photo so that it fills the iPhoto window, double-click its thumbnail, or select the photo and press the spacebar. Tip: Maximize your viewing area: choose Window > Zoom or click the green zoom button in the upper-left corner.
To return to thumbnails, double-click the magnified photo or press the spacebar.
Full-screen variation. To fill the entire screen with ...